The present invention relates to dietary programs for dairy cattle and, more specifically, to the protein portion of dietary programs designed to increase milk production of dairy cows.
It has been recognized that the protein content of a dairy cow's diet is an important factor in the quantity of milk produced. Much research has been devoted to determining the relationship between total protein intake and milk production. In this context, the term "total protein" is used to denote both protein substances and non-protein nitrogen sources such as urea. It is standard procedure to calculate the total protein content of a feed material based on its nitrogen content. Since protein contains approximately 16% nitrogen, total protein content is expressed as 6.25 times the nitrogen percentage content of a given material. That is, if the composition of a material includes 2% nitrogen, its total protein content is 12.5% (6.25 .times. 2%).
In the unique digestive system of ruminant animals, a portion of the food is broken down by the fluid and microorganisms present in the rumeno-reticular compartment, the first and largest of the stomach compartments. Certain protein substances are degraded to soluble peptides, amino acids and/or ammonia in the rumen, while others remain chemically intact until digested in the abomasum or small intestine. For purposes of the present discussion, such substances are termed soluble and insoluble proteins, respectively. Thus, the total protein content of a given ration may be expressed in terms of the percentages of soluble and insoluble protein.
The prior art includes studies of ruminant nutrition which suggest that weight gain may be accelerated in beef cattle and wool growth increased in sheep by inhibiting protein breakdown until the later stages of the digestive process. For example, coating with fats and vegetable oils, heat treatment and reaction with specific chemicals are among the procedures suggested for improving the nutrient usefulness for sheep and beef cattle. The implications of prior research in the area of protein solubility, as previously defined, are confined to weight gain and wool growth, and suggest that the level of protein solubility should be as low as possible. That is, for the best body and wool growth, ideally, all protein should be insoluble in the rumen.